If I remember correctly, I'm supposed to wait 6000 miles before switching to a synthetic oil in my new engine. Is this right?

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Michelle
92 Formula 350
91 Z28

 

I dunno, I just switched from mineral to synthetic in one change in my 305. Just switched right over. I dunno if that was a no no, but there is no blue smoke. Why can't you use it from start in a new engine?

 

Define "new".

The engine in a "new" car can be switched over to synthetic as soon as you get it home. Some (Vettes & Vipers, for instance) come with it factory-fill.

If a "new" rebuild, it is wise to go a few hundred or thousand miles or so with petroleum oil to allow the rings and cylinder walls to seat to each other (the higher lubricity of the synthetic will slow the wear-in process). 6k is probably more than needed, though.

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82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R4. 2.93 limited slip. 2-1/2" cat-back, ZZ3 intake, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LG4 CC system w/'87 LB9 block, ZZ3 cam, ported World 305 heads, Hooker 2055 headers, 3" Catco cat & 3" catback, restalled TC, Spohn SFCs).
57 Bel Air, my 1st car. '66 396, 9.7 CR forged TRWs, Weiand Action+, Holley 750VS w/4150 conversion, GK 270 cam, Magnum rockers, Jacobs Omnipack, 1-3/4" Hedders & 3" Warlocks, TH400 w/TCI Sat Night Special conv & Trans-Scat shift kit, MegaShifter, 3.08 8.2" 10-bolt w/Powertrax, AMSOIL syn lubes bumper-to-bumper. Idles smooth @ 600 RPM in D. Best 15.02/95.06 @ 5800' Bandimere (corrected 13.93/102.4 @ sea level).

 

on any engine i do i first start it on 30w pennzoil and change it after 30 minutes or so with 30w pennzoil and them after a few 1000 miles i go with synthetic. if you've never tried amsoil you ought to consider it.

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ICON Motorsports
1st & 3rd
MM Black Diamond 538 F&AM

 

As soon as the brand new vehicle comes off the zone delivery truck, you can switch to synthetic and not void the warranty. With some engines, as 5-7 stated, you'll void the warranty without synthetic oil, since they come from the factory with Mobil 1 in the sump.

As another precaution, you mention "synthetic oil" as a generic term. It is important to remember that not all synthetics are the same, and some are not compatible. Most synthetic lubricants designed for engine lubrication have a polyalphaolefin and dialkylated benzene base, and some are polyol esters. Do not mix the two, nor should you mix any synthetic lubricants that aren't of the same type. If you use Mobil 1, keep everything else synthetic out of the sump. In an emergency when no Mobil 1 is available, it is better and safer to mix mineral oil (regular oil) into the sump rather than chance mixing synthetics. Mixing the bases can cause solids to precipitate out of the oil and can reduce the effective lubricity of the mix to almost nothing. You'll be shopping for an engine in about 50 miles.

Additionally, don't use 5W-30 synthetics. If you understand what a synthetic molecule does, you'll realize that the lubricity of the 5W formula is lower than 10W formulas, and the cold pumping and lubrication properties are no better. There is no advantage, since the antiquated SAE grading system for mineral based engine oils doesn't even really apply to synthetics. The scale was basically proven faulty by synthetics, and the numbers are relatively meaningless in real lubrication terms. Always use the ISO viscosity or SUS test viscosities for oils, and you'll have a lot better handle on what's going on. The SAE system was intended to make oil selecton easy for the average moron who doesn't know any better, and is really an insult to the countless man/hours of research done over the last century to test and grade oils correctly.

Don't listen to Buford at the local repair shop - it isn't likely that he is much of a lubrication technician. Check the data at the Exxon-Mobil web site if you have more questions about correct choice and applications.

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Later,
Vader
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Justice and Freedom will Prevail

 

You'll find various opinions, so here is mine...

Flat tappet cammed, apx. 3,000 mi. after break-in.
Roller cammed, apx. 1,500 mi. after break-in.

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"Question with boldness even the existence of a *** ; because, if there be one, he must more approve of the homage of reason, than that of blind-folded fear."

-Thomas Jefferson

 

FWIW here's my opinion:

Roller cam — many (Vettes for instance) come from the factory filled with synthetic, so no wait required

Flat-tappet cam — after break-in at time of first oil change (1000 miles)

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"So many Mustangs, so little time..."
ICON Motorsports